The construction and the regulatory mechanisms of the immune system in mammals have been studied extensively in recent years.
Leucocytes or white blood corpuscles, which are colorless ameboid cells, occur in the blood plasma of many animals. Macrophages are a type of leucocyte which are derived from blood monocytes that have migrated into tissues and have differentiated. They are largely phagocytic and ingest particulate materials including microbes. Macrophages also play important roles in immuno-regulation, control of inflammation, regulation of metabolism, and control of growth, particularly when activated by lymphokines or immunological protein factors such as interleukin-1 ("IL-1") and tumor necrosis factor.
Macrophages are also important accessory cells for presentation of antigens to T-lymphocytes. T-lymphocytes are responsible for the development of cellular immunity. T-lymphocytes typically comprise about 70% of the total lymphocytes and about 80% of the lymph nodes.
T-lymphocytes which have been activated by IL-1 and a mitogenic agent such as concanavalin A or a specific antigen produce interleukin-2 ("IL-2"), a T-lymphocyte growth factor. IL-2, in turn, binds to specific receptors on various T-cells, activating other cells and stimulating T-cell growth and differentiation.
Interferons are another group of proteins released from T-lymphocytes that also have important immunological functions including eliciting anti-viral and anti-cancer responses. Furthermore, interferons enhance other immunological responses such as phagocytosis of macrophages, the activities of natural killer cells (lymphoid cells that kill a large range of tumor cell targets), K-cells (part of the antigen-antibody response), and T-cells; and the regulation of antibody production.
Many monothiophene derivatives are isosteres of benzene derivatives and have been investigated as human and veterinary drugs. Press, "Pharmacologically Active Compounds", Heterocyclic in Compounds, Vol. 44: pt. 1, Chptr. V, John Wiley and Sons (1985). Most of these monothiophene derivatives are pharmaceutically inferior to benzene derivatives and are not commercially available.
Several dithiophene derivatives have been studied to determine their pharmacological activities. For example, Zemtsova et al., Khim Farm Zh., 7(8), 13 (1973); Vakhreeva et al., Khim-Farm. Zh., 7(3), 24 (1973); Vakhreeva et al., Khim-Farm. Zh., 6(1), 24 (1972) reported low anti-bacterial activity of certain dithiophene compounds.
The Compositae or daisy plant family includes about 1000 genera and about 20,000 species. Approximately 66 genera and 230 species have been collected in Chinese Medicine Books. These genera and species have been found to decrease body heat, detoxicate, reduce edema, relieve pain, treat tumors, and cure sores. Analysis of these particular Compositae reveals that they all contain thiophene derivatives. These thiophene derivatives are not found in other higher plants.